Big accidentally knocks two holes in the living room wall - two of many holes in the wall that have been covered up by paintings. They need to paint another picture - but what to paint? Big and Small decide to paint a portrait of Ruby, who happens to be quietly sitting and reading in the garden. Big and Small have very different styles of painting - Small's hurls himself and the paint at the canvas while Big takes precise measurements and makes careful drawings. At the end of a day being an artist, Small has a picture which is all sky and garden but no Ruby. Big, however, has a tiny picture of Ruby but no sky or garden... But when they put the paintings together it's a perfect picture and perfect for covering up both of the holes in the wall. Big and Small hold a competition to see who can paint the best picture of Ruby.